The present invention relates to an apparatus and method for repairing pipe, such as underground sewer pipe and the like.
Prior methods for repairing damaged sections of pipe include moving a liner tube impregnated with a resinous material capable of curing and hardening to a position within the pipe where the damaged portion is located. Once the liner tube is positioned within the host pipe, it is pressurized, causing the liner to press against the interior wall of the host pipe, and the liner is cured by applying heat, such as with steam or hot water. These liners can also be cured at ambient temperatures by a chemical mixture which generates an exothermic reaction or by ultraviolet light. The liner tube forms an interior liner in the pipe for the pipeline being repaired. Such a process is commonly known as cured-in-place pipelining.
The liner tube is positioned within the pipe by pulling, pushing or inverting the liner. Pulling or pushing a liner into position within a pipe can be an efficient process, particularly in situations where the liner must only travel a short distance and need not navigate significant bends in the pipe. Typically, a flat sheet liner is wrapped around an inflation plug to form a tube with the longitudinal edges of the sheet overlapping. The inflation plug with liner is then pushed or pulled into position adjacent the damaged section of pipe.
Although a pull-in-place or push-in-place installation is feasible in many instances, problems remain. For example, prior art lining tubes are typically made of a fabric material that is resin absorbent. Once the resin is applied to the liner, there is nothing around the outside of the liner to contain the resin. Consequently, resin is wiped off of the liner when the liner rubs against the interior of the host pipe as the liner is either pulled or pushed into position. Workers must also take great care so as to not come into contact with the resin and also avoid contaminating the exposed resin impregnated liner.
Prior art liners pushed or pulled in place are also not well suited for lining at bends in the pipeline. Flat sheet liners with overlapping edges are not capable of stretching or expanding sufficiently to avoid folds in the liner when pressed against the interior of the host pipe. In addition, flat sheet style liners must be banded, strapped, tied or otherwise attached with fasteners to the inflation plug to avoid falling off the plug prior to inflating the plug and pressing the liner against the interior of the host pipe.
In light of the foregoing, the primary objective of the present invention is to provide an improved method and apparatus for lining pipe.
Another objective of the present invention is to provide a new resin absorbent liner that contains the resin in the liner prior to stretching the liner and pressing it against the interior of the host pipe.
Another objective of the present invention is to provide a new lining apparatus for pull-in-place or push-in-place applications that prevents resin from being wiped off of the liner as it is moved into the pipe, yet allows the resin to contact the interior of the host pipe once the liner is expanded or stretched under pressure.
Another objective of the present invention is to provide a new lining apparatus and method for effectively lining at bends and turns in the pipeline.
A still further objective of the present invention is to provide a new lining apparatus which is economical to manufacture, durable in use and efficient in operation.